Translating cowl thrust reverser system with over-stow unlocking capability

ABSTRACT

A thrust reverser system for a turbine engine includes a support structure, a transcowl, a door, a lock, and a first elastic element. The transcowl is mounted on the support structure and is translatable between a stowed position, a deployed position, and an over-stow position. The door is pivotally coupled to the support structure and is rotatable between at least a first position, a second position, and a third position. The lock is movable between a locked position, to prevent transcowl translation toward the deployed position, and an unlocked position, to allow transcowl translation toward the deployed position. The lock is only able to move to the unlocked position when the transcowl is in the over-stow position. The first elastic element is disposed within the stowed position aperture and, when engaging both the support structure and the transcowl, supplies a force to the transcowl.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/019,055, filed Feb. 9, 2016, now U.S. Pat. No.10,415,504.

TECHNICAL FIELD

The present invention relates to a thrust reverser system for a turbineengine, and more particularly to a thrust reverser system that includesover-stow unlocking capability.

BACKGROUND

When turbine-powered aircraft land, the wheel brakes and the imposedaerodynamic drag loads (e.g., flaps, spoilers, etc.) of the aircraft maynot be sufficient to achieve the desired stopping distance. Thus, theengines on most turbine-powered aircraft include thrust reversers.Thrust reversers enhance the stopping power of the aircraft byredirecting the engine exhaust airflow in order to generate reversethrust. When stowed, the thrust reverser typically forms a portion theengine nacelle and forward thrust nozzle. When deployed, the thrustreverser typically redirects at least a portion of the airflow (from thefan and/or engine core exhaust) forward and radially outward, to helpdecelerate the aircraft.

Various thrust reverser designs are commonly known, and the particulardesign utilized depends, at least in part, on the engine manufacturer,the engine configuration, and the propulsion technology being used.Thrust reverser designs used most prominently with turbofan engines fallinto two general categories: (1) fan flow thrust reversers, and (2)mixed flow thrust reversers. Fan flow thrust reversers affect only thebypass airflow discharged from the engine fan. Whereas, mixed flowthrust reversers affect both the fan airflow and the airflow dischargedfrom the engine core (core airflow).

Fan flow thrust reversers are typically used on relatively high-bypassratio turbofan engines. Fan flow thrust reversers include so-called“Cascade-type” or “Translating Cowl-type” thrust reversers. Fan flowthrust reversers are generally positioned circumferentially around theengine core aft of the engine fan and, when deployed, redirect fanbypass airflow through a plurality of cascade vanes disposed within anaperture of a reverse flow path. Typically, fan flow thrust reverserdesigns include one or more translating sleeves or cowls (“transcowls”)that, when deployed, open an aperture, expose cascade vanes, and createa reverse flow path. Fan flow reversers may also include so-called pivotdoors or blocker doors which, when deployed, rotate to block the forwardthrust flow path.

In contrast, mixed flow thrust reversers are typically used withrelatively low-bypass ratio turbofan engines. Mixed flow thrustreversers typically include so-called “Target-type,” “Bucket-type,” and“Clamshell Door-type” thrust reversers. These types of thrust reverserstypically use two or more pivoting doors that rotate, simultaneouslyopening a reverse flow path through an aperture and blocking the forwardthrust flow path. However, a transcowl type thrust reverser could alsobe configured for use in a mixed flow application. Regardless of type,mixed flow thrust reversers are necessarily located aft or downstream ofthe engine fan and core, and often form the aft part of the enginenacelle.

Transcowl type thrust reversers transition from the forward thrust stateto the reverse thrust state by translating the transcowl aft so as toopen a reverse thrust aperture, and simultaneously rotating a set ofdoors so as to obstruct the forward thrust nozzle. This coordinatedmotion between the transcowl and the doors is typically achieved by theuse of a linkage rod arrangement, which connects the doors to thetranscowl so that translational motion of the transcowl causesrotational motion of the doors.

Typically, these types of thrust reverser systems are equipped with aredundant locking system to ensure that inadvertent in-flight deploymentis extremely improbable. This locking system is typically arranged toprevent the transcowl from translating aft until it is commanded to doso. Though highly unlikely, it is postulated that the presently knownlocking systems could become inoperable, resulting in an uncommanded,uncontrolled, and undesirable deployment of the transcowl.

Hence, there is a need for means of preventing an uncommanded deploymentof thrust reverser system transcowls. The present invention addresses atleast this need.

BRIEF SUMMARY

This summary is provided to describe select concepts in a simplifiedform that are further described in the Detailed Description. Thissummary is not intended to identify key or essential features of theclaimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

In one embodiment, a thrust reverser system for a turbine engineincludes a support structure, a transcowl, a door, a lock, and a firstelastic element. The support structure is configured to be mounted tothe turbine engine. The transcowl is mounted on the support structureand is axially translatable, relative to the support structure, between(i) a stowed position, in which the transcowl is displaced from thesupport structure by a first distance to form a stowed positionaperture, (ii) a deployed position, in which the transcowl is displacedfrom the support structure a second distance that is larger than thefirst distance, and (iii) an over-stow position, in which the transcowlis displaced from the support structure by a third distance that is lessthan the first distance, thereby decreasing the size of the stowedposition aperture. The door is pivotally coupled to the supportstructure and is rotatable between at least a first position, a secondposition, and a third position when the transcowl translates between thestowed position, the deployed position, and the over-stow position,respectively. The door is configured, when it is in the second position,to redirect engine airflow to thereby generate reverse thrust. The lockis coupled to the support structure and is movable between a lockedposition, in which transcowl translation toward the deployed position isprevented, and an unlocked position, in which transcowl translationtoward the deployed position is allowed. The lock is configured so thatit is prevented from moving from the locked position to the unlockedposition when the transcowl is in the stowed position and is only ableto move to the unlocked position when the transcowl is in the over-stowposition. The first elastic element is disposed within the stowedposition aperture and engages both the support structure and thetranscowl at least when the transcowl is in and between the stowed andover-stow positions. The first elastic element is configured, whenengaging both the support structure and the transcowl, to supply a forceto the transcowl that biases the transcowl toward the deployed position.The force in the over-stow position is greater than the force in thestowed position.

In another embodiment, a thrust reverser system for a turbine engineincludes a support structure, a transcowl, a plurality of doors, a lock,and a first elastic element. The support structure is configured to bemounted to the engine. The transcowl is mounted on the support structureand is axially translatable, relative to the support structure, between(i) a stowed position, in which the transcowl is displaced from thesupport structure by a first distance to form a stowed positionaperture, (ii) a deployed position, in which the transcowl is displacedfrom the support structure a second distance that is larger than thefirst distance, and (iii) an over-stow position, in which the transcowlis displaced from the support structure by a third distance that is lessthan the first distance, thereby decreasing the size of the stowedposition aperture. The doors are pivotally coupled to the supportstructure, and each door is rotatable between at least a first position,a second position, and a third position when the transcowl translatesbetween the stowed position, the deployed position, and the over-stowposition, respectively. Each door is configured, when it is in thesecond position, to redirect engine airflow to thereby generate reversethrust. The lock is coupled to the support structure and is movablebetween a locked position, in which transcowl translation toward thedeployed position is prevented, and an unlocked position, in whichtranscowl translation toward the deployed position is allowed. The lockis configured so that it is prevented from moving from the lockedposition to the unlocked position when the transcowl is in the stowedposition and is only able to move to the unlocked position when thetranscowl is in the over-stow position. The first elastic element isdisposed within the stowed position aperture and engages both thesupport structure and the transcowl at least when the transcowl is inand between the stowed and over-stow positions. The first elasticelement is configured, when engaging both the support structure and thetranscowl, to supply a force to the transcowl that biases the transcowltoward the deployed position. The force in the over-stow position isgreater than the force in the stowed position.

In yet another embodiment, a turbofan or turbojet engine includes a gasturbine engine and a nacelle coupled to and at least partiallysurrounding the gas turbine engine. The nacelle comprises a thrustreverser system that includes a support structure, a transcowl, aplurality of doors, a lock, a first elastic element, and a secondelastic element. The support structure is configured to be mounted tothe engine. The transcowl is mounted on the support structure and isaxially translatable, relative to the support structure, between (i) astowed position, in which the transcowl is displaced from the supportstructure by a first distance to form a stowed position aperture, (ii) adeployed position, in which the transcowl is displaced from the supportstructure a second distance that is larger than the first distance, and(iii) an over-stow position, in which the transcowl is displaced fromthe support structure by a third distance that is less than the firstdistance, thereby decreasing the size of the stowed position aperture.The doors are pivotally coupled to the support structure, and each dooris rotatable between at least a first position, a second position, and athird position when the transcowl translates between the stowedposition, the deployed position, and the over-stow position,respectively. Each door is configured, when it is in the secondposition, to redirect engine airflow to thereby generate reverse thrust.The lock is coupled to the support structure and is movable between alocked position, in which transcowl translation toward the deployedposition is prevented, and an unlocked position, in which transcowltranslation toward the deployed position is allowed. The lock isconfigured so that it is prevented from moving from the locked positionto the unlocked position when the transcowl is in the stowed positionand is only able to move to the unlocked position when the transcowl isin the over-stow position. The first elastic element is disposed withinthe stowed position aperture and engages both the support structure andthe transcowl at least when the transcowl is in and between the stowedand over-stow positions. The first elastic element is configured, whenengaging both the support structure and the transcowl, to supply a forceto the transcowl that biases the transcowl toward the deployed position.The force in the over-stow position greater than the force in the stowedposition. The second elastic elements are coupled to the transcowl. Eachof the second elastic elements engages one of the doors at least whenthe doors are in the third position. Each of the second elastic elementsis configured, at least when the door is in the third position, tosupply a bias force that biases the door it engages toward the firstposition.

Furthermore, other desirable features and characteristics of the thrustreverser system will become apparent from the subsequent detaileddescription and the appended claims, taken in conjunction with theaccompanying drawings and the preceding background.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction withthe following drawing figures, wherein like numerals denote likeelements, and wherein:

FIGS. 1 and 2 depict a turbofan engine equipped with a mixed flow thrustreverser system, and with the thrust reverser system in a stowedposition and deployed position, respectively;

FIGS. 3 and 4 depict a turbofan engine equipped with a fan flow thrustreverser system, and with the thrust reverser system in a stowedposition and deployed position, respectively;

FIG. 5 depicts a close-up cross section view of a first portion of oneembodiment of a thrust reverser system that may be implemented in theturbofan engines of FIGS. 1-4 with the transcowl in a stowed position;

FIG. 6 depicts the close-up cross section view of the first portion ofthe thrust reverser system of FIG. 5 but with the transcowl in anover-stow position;

FIG. 7 depicts a close-up cross section view of a second portion of oneembodiment of a thrust reverser system that may be implemented in theturbofan engines of FIGS. 1-4 with the transcowl and doors in a stowedposition;

FIG. 8 depicts a close-up cross section view of the second portion ofthe thrust reverser system of FIG. 7 but with the transcowl and doors inan over-stow position;

FIGS. 9-11 depict one embodiment of a locking system that may beimplemented in the thrust reverser systems of FIGS. 1-4;

FIGS. 12-14 depict another embodiment of a locking system that may beimplemented in the thrust reverser systems of FIGS. 1-4; and

FIGS. 15-17 depict yet another embodiment of a locking system that maybe implemented in the thrust reverser systems of FIGS. 1-4.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. As used herein, the word “exemplary” means “serving as anexample, instance, or illustration.” Thus, any embodiment describedherein as “exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. All of the embodiments describedherein are exemplary embodiments provided to enable persons skilled inthe art to make or use the invention and not to limit the scope of theinvention which is defined by the claims. Furthermore, there is nointention to be bound by any expressed or implied theory presented inthe preceding technical field, background, brief summary, or thefollowing detailed description.

A turbofan engine is a component of an aircraft's propulsion system thattypically generates thrust by means of an accelerating mass of gas.Simplified cross section views of a traditional aircraft turbofan engine100 are depicted in FIGS. 1-4. In particular, FIGS. 1 and 2 depict theengine 100 equipped with a mixed flow thrust reverser system, and withthe thrust reverser system in a stowed position and deployed position,respectively, and FIGS. 3 and 4 depict the engine 100 equipped with afan flow thrust reverser system, and with the thrust reverser system ina stowed position and deployed position, respectively.

Referring first to FIGS. 1 and 2, the turbofan engine 100 includes a gasturbine engine 102 that is encased within an aerodynamically smoothouter covering, generally referred to as the nacelle 104. Ambient air106 is drawn into the nacelle 104 via a rotationally mounted fan 108 tothereby supply engine airflow. A portion of the engine airflow is drawninto the gas turbine engine 102, where it is pressurized, and mixed withfuel and ignited, to generate hot gasses known as core flow 103. Theremainder of engine airflow bypasses the gas turbine engine 102 and isknown as fan flow 105. The core flow 103 and the fan flow 105 mixdownstream of the gas turbine engine 102 to become the engine exhaustflow 107, which is discharged from the turbofan engine 100 to generateforward thrust.

The nacelle 104 comprises a mixed flow thrust reverser system 110. Thethrust reverser system 110 includes a support structure 112, an annulartranslatable cowl, or transcowl 114, and one or more doors 116 (two inthe depicted embodiment). The transcowl 114 is mounted on the supportstructure 112 and has an inner surface 118 and an outer surface 122. Thetranscowl 114 is axially translatable, relative to the support structure112, between a stowed position, which is the position depicted in FIG.1, a deployed position, which is the position depicted in FIG. 2, and anover-stow position, which is depicted and described further below. Inthe stowed position, the transcowl 114 is displaced from the supportstructure 112 by a first distance to form a stowed position aperture113. In the deployed position, the transcowl 114 is displaced from thesupport structure 112 by a second distance, which is larger than thefirst distance, to form a reverse thrust aperture 202 (see FIG. 2). Aswill be described further below, in the over-stow position, thetranscowl 114 is displaced from the support structure 112 by a thirddistance that is less than the first distance, thereby decreasing thesize of the stowed position aperture 113.

Each of the one or more doors 116, at least in the depicted embodiment,is pivotally coupled to the support structure 112. It will beappreciated, however, that in other embodiments each door 116 couldinstead be coupled to any component that is rigidly attached to theturbofan engine. Regardless, each door 116 is rotatable between a firstposition, which is the position depicted in FIG. 1, a second position,which is the position depicted in FIG. 2, and a third position, which isdescribed further below. More specifically, each door 116 is rotatablebetween the first position, the second position, and the third positionwhen the transcowl 114 translates between the stowed position, thedeployed position, and the over-stow position, respectively. As isgenerally known, each door 116 is configured, when it is in the secondposition, to redirect at least a portion of the engine airflow throughthe reverse thrust aperture 202 to thereby generate reverse thrust. Inparticular, at least a portion of the engine exhaust flow 107 (e.g.,mixed core flow 103 and fan flow 105) is redirected through the reversethrust aperture 202.

Referring now to FIGS. 3 and 4, the turbofan engine 100 equipped with afan flow thrust reverser system 310 will be briefly described. Beforedoing so, however, it is noted that like reference numerals in FIGS. 1-4refer to like parts, and that descriptions of the like parts of thedepicted turbofan engines 100 will not be repeated. The notabledifference between the turbofan engine 100 depicted in FIGS. 3 and 4 isthat the fan flow thrust reverser system 310 is disposed furtherupstream than that of the mixed flow thrust reverser system 110 depictedin FIGS. 1 and 2.

As with the mixed flow thrust reverser system 110, the depicted fan flowthrust reverser system 310 includes the support structure 112, thetranscowl 114, and the one or more doors 116 (again, two in the depictedembodiment). Moreover, each door 116 is rotatable between a firstposition, which is the position depicted in FIG. 3, a second position,which is the position depicted in FIG. 4, and a third position, which isdescribed further below. Similarly, each door 116 is rotatable betweenthe first position, the second position, and the third position when thetranscowl 114 translates between the stowed position, the deployedposition, and the over-stow position, respectively. As is generallyknown, each door 116 is configured, when it is in the second position,to redirect at least a portion of the engine airflow through the reversethrust aperture 202 to thereby generate reverse thrust. In this case,however, only fan bypass flow 105 is redirected through the reversethrust aperture 202.

As FIGS. 1-4 also depict, the thrust reverser systems 110, 310additionally include a plurality of actuators 124 (only one depicted)and one or more locks 126 (only one depicted). The actuators 124 arecoupled to the support structure 112 and the transcowl 114, and areconfigured to supply an actuation force to the transcowl 114. It will beappreciated that the actuators 124 may be implemented using any one ofnumerous types of electric, hydraulic, or pneumatic actuators.Regardless of the type of actuators 124 that are used, each isresponsive to commands supplied from a non-illustrated actuation controlsystem to supply an actuation force to the transcowl 114, to therebymove the transcowl 114 between the stowed position, the deployedposition, and the over-stow position.

Each lock 126 is coupled to the support structure 112 and is movablebetween a locked position and an unlocked position. It will beappreciated that the locks 126 may be variously configured, and may bemoved between the locked and unlocked positions electrically,hydraulically, or pneumatically. Various particular configurations aredescribed further below. Regardless, of the particular configurationthat is used, each lock 126 is responsive to commands supplied from thenon-illustrated actuation control system to move between the locked andunlocked positions. In the locked position, transcowl translation fromthe stowed position into the deployed position is prevented, and in theunlocked position, transcowl translation from the stowed position intothe deployed position is allowed. Moreover, each lock 126 is configuredsuch that, when the transcowl 114 is in the stowed position, movement ofthe lock from the locked position to the unlocked position is prevented.Each lock can move to the unlocked position only when the transcowl 114is in the over-stow position.

With reference now to FIGS. 5 and 6, it is seen that both thrustreverser systems 110, 310 additionally include a first elastic element502. The first elastic element 502 is disposed within the stowedposition aperture 113 and engages both the support structure 112 and thetranscowl 114 at least when the transcowl 114 is in the stowed position(FIG. 5), the over-stow position (FIG. 6), and any position betweenthese two positions. The first elastic element 502 is configured, whenengaging both the support structure 112 and the transcowl 114, to supplya force to the transcowl 114 that biases the transcowl 114 toward thedeployed position. As may be appreciated, the force that the firstelastic element 502 supplies to the transcowl 114 when the transcowl 114is in the over-stow position is greater than the force it supplies whenthe transcowl 114 is in the stowed position.

It will be appreciated that the first elastic element 502 may bevariously mounted. In the depicted embodiment the first elastic element502 is mounted on the support structure 112 and extends into the stowedposition aperture 113. In other embodiments, however, the first elasticelement 502 could be mounted on the transcowl 114. It will additionallybe appreciated that the first elastic element 502 may be formed of anyone of numerous elastic or elastomeric materials. For example, it may beformed of rubber, plastic, metal, or composite material. In the depictedembodiment, however, it is formed of a fiber reinforced silicone rubber.Moreover, although a single first elastic element 502 is depicted,multiple first elastic elements 502 could be used.

Turning now to FIGS. 7 and 8, the depicted thrust reverser systems 110,310 further include a plurality of second elastic elements 702 (only onedepicted) and one or more linkage assemblies 704 (only one depicted).The second elastic elements 702 are each coupled to the transcowl 114and extend inwardly therefrom. More specifically, at least in thedepicted embodiment, the second elastic elements 702 are coupled to theinner surface 118 of the transcowl 114, and extend into a gap 706 thatis defined between the inner surface 118 of the transcowl 114 and theouter surface 708 of each door 116. The second elastic elements 702 aresized and configured to engage one of the doors 116 at least when thedoors 116 are in the third position. In the depicted embodiment, thesecond elastic elements 702 are each sized and configured to engage oneof the doors 116 when the doors 116 are in both the first position (FIG.7) and the third position (FIG. 8). Moreover, each of the second elasticelements 702 is configured, at least when the doors 116 are in the thirdposition, to supply a bias force that biases the door 116 it engagestoward the first position.

It will be appreciated that, like the first elastic element 502, thesecond elastic elements 702 may be formed of any one of numerous elasticor elastomeric materials. For example, each may be formed of rubber,plastic, metal, or composite material. In the depicted embodiment,however, each is formed of a fiber reinforced silicone rubber.

Each linkage assembly 704 is coupled to the transcowl 114 and to one ofthe doors 116 and is configured to cause the doors 116 to rotate betweenthe first, second, and third positions when the transcowl 114 translatesbetween the stowed, deployed position, and over-stow positions,respectively. In the depicted embodiment, each linkage assembly 704 isimplemented using a plurality of link elements 704-1, 704-2 so as toachieve the necessary motion and transmit the necessary force betweenthe door 116 and the transcowl 114. Preferably, the thrust reversersystem includes redundant linkage assemblies 704 such that if onelinkage assembly were unable to transmit the necessary force, theremaining linkage assembly(ies) would still transmit the force. It willbe appreciated that although the linkage assembly 704 is depicted asbeing implemented with two link elements 704-1, 704-2, it couldadditionally be implemented using more or fewer link elements.

The locks 126, as previously noted, are configured such that, when thetranscowl 114 is in the stowed position movement of the lock from thelocked position to the unlocked position is prevented. Each lock canmove to the unlocked position only when the transcowl 114 is moved tothe over-stow position. The locks 126 and associated structure (i.e.,the support structure 112 and transcowl 114) may be variously configuredto implement this functionality. Some example lock 126 configurationsare depicted in FIGS. 9-17, and will now be described.

Referring first to FIGS. 9-11, in one embodiment each lock 126 includesa lock actuator 1102 and a pin 1104. The lock actuator 1102 is mountedon the support structure 112 and is responsive to commands received fromthe non-illustrated actuation control system to move between the lockedand unlocked positions. The pin 1104 is coupled to, and extends from,the lock actuator 1102 to an engagement end 1106. The pin 1104, inresponse to lock actuator movement between the locked position and theunlocked position, translates between an extended position (FIGS. 9 and10) and a retracted position (FIG. 11), respectively. The pin 1104extends through an opening 1108 in the support structure 112 and has agroove 1112 formed in the engagement end 1106.

As FIG. 9 depicts, when the pin 1104 is in the extended position and thetranscowl 114 is in the stowed position, a portion of the transcowl 114is disposed in the groove 1112. Thus, the transcowl 114 is preventedfrom translating toward the deployed position, and the pin 1104 isprevented from translating to the retracted position. However, as FIG.10 depicts, the transcowl 114 may translate from the stowed position tothe over-stow position. As a result, and as depicted in FIG. 11, the pin1104 may then translate to the retracted position, allowing thetranscowl 114 to translate to the deployed position.

Referring now to FIGS. 12-14, in another embodiment each lock 126extends through an opening 1402 in the transcowl 114 and includes a lockactuator 1102, a pin 1404, and a plurality of lock segments 1406. Thelock actuator 1102 is mounted on the support structure 112 and isresponsive to commands received from the non-illustrated actuationcontrol system to move between the locked and unlocked positions. Thelock pin 1404 and segments 1406 are each responsive to lock actuatormovement between the locked position and the unlocked position to movebetween an extended position (FIGS. 12 and 13) and a retracted position(FIG. 14), respectively.

As FIG. 12 depicts, when the lock segments 1406 are in the extendedposition and the transcowl 114 is in the stowed position, a portion ofthe transcowl 114 is engaged by each of the lock segments 1406. Thus,the transcowl 114 is prevented from translating toward the deployedposition and the lock segments 1406 are prevented from moving to theretracted position. However, as FIG. 13 depicts, the transcowl 114 maytranslate from the stowed position to the over-stow position. As aresult, and as depicted in FIG. 14, the lock segments 1406 may then moveto the retracted position, allowing the transcowl 114 to translate tothe deployed position.

In yet another embodiment, which is depicted in FIGS. 15-17, each lock126 includes a lock actuator 1102, a rod 1702, and a hook 1704. The lockactuator 1102 is mounted on the support structure 112 and is responsiveto commands received from the non-illustrated actuation control systemto move between the locked and unlocked positions. The hook 1704 iscoupled to the lock actuator 1102, by rod 1702, and is rotationallymounted on the support structure 112. The hook 1704, in response to lockactuator movement between the locked position and the unlocked position,rotates between a first rotational position (FIGS. 15 and 16) and asecond rotational position (FIG. 17), respectively. The hook 1704extends through an opening 1706 in the support structure 112 and into anopening 1708 in the transcowl 114.

As FIG. 15 depicts, when the hook 1704 is in the first rotationalposition and the transcowl 114 is in the stowed position, a portion ofthe transcowl 114 is engaged by the hook 1704. Thus, the transcowl 114is prevented from translating toward the deployed position, and the hook1704 is prevented from rotating to the second rotational position.However, as FIG. 16 depicts, the transcowl 114 may translate from thestowed position to the over-stow position. As a result, and as depictedin FIG. 17, the hook 1704 may then rotate to the second rotationalposition, allowing the transcowl 114 to translate to the deployedposition.

In this document, relational terms such as first and second, and thelike may be used solely to distinguish one entity or action from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions. Numericalordinals such as “first,” “second,” “third,” etc. simply denotedifferent singles of a plurality and do not imply any order or sequenceunless specifically defined by the claim language. The sequence of thetext in any of the claims does not imply that process steps must beperformed in a temporal or logical order according to such sequenceunless it is specifically defined by the language of the claim. Theprocess steps may be interchanged in any order without departing fromthe scope of the invention as long as such an interchange does notcontradict the claim language and is not logically nonsensical.

Furthermore, depending on the context, words such as “connect” or“coupled to” used in describing a relationship between differentelements do not imply that a direct physical connection must be madebetween these elements. For example, two elements may be connected toeach other physically, electronically, logically, or in any othermanner, through one or more additional elements.

While at least one exemplary embodiment has been presented in theforegoing detailed description of the invention, it should beappreciated that a vast number of variations exist. It should also beappreciated that the exemplary embodiment or exemplary embodiments areonly examples, and are not intended to limit the scope, applicability,or configuration of the invention in any way. Rather, the foregoingdetailed description will provide those skilled in the art with aconvenient road map for implementing an exemplary embodiment of theinvention. It being understood that various changes may be made in thefunction and arrangement of elements described in an exemplaryembodiment without departing from the scope of the invention as setforth in the appended claims.

What is claimed is:
 1. A thrust reverser system for a turbine engine,comprising: a support structure configured to be mounted to the turbineengine; a transcowl mounted on the support structure and including aninner surface, the transcowl axially translatable, relative to thesupport structure, between (i) a stowed position, in which the transcowlis displaced from the support structure by a first distance to form astowed position aperture, (ii) a deployed position, in which thetranscowl is displaced from the support structure a second distance thatis larger than the first distance, and (iii) an over-stow position, inwhich the transcowl is displaced from the support structure by a thirddistance that is less than the first distance, thereby decreasing thesize of the stowed position aperture; a door including an outer surfaceand spaced apart from the transcowl to define a gap between the innersurface of the transcowl and the outer surface of the door, the doorpivotally coupled to the support structure and rotatable between atleast a first position, a second position, and a third position when thetranscowl translates between the stowed position, the deployed position,and the over-stow position, respectively, the door configured, when itis in the second position, to redirect engine airflow to therebygenerate reverse thrust; an actuator coupled to the support structureand the transcowl and configured to supply an actuation force to movethe transcowl between the stowed position, the deployed position, andthe over-stow position; a lock coupled to the support structure andmovable between a locked position, in which transcowl translation towardthe deployed position is prevented, and an unlocked position, in whichtranscowl translation toward the deployed position is allowed, the lockconfigured so that it is prevented from moving from the locked positionto the unlocked position when the transcowl is in the stowed positionand is only able to move to the unlocked position when the transcowl isin the over-stow position; and a first elastic element disposed withinthe stowed position aperture and engaging both the support structure andthe transcowl at least when the transcowl is in and between the stowedand over-stow positions, the first elastic element configured, whenengaging both the support structure and the transcowl, to supply a forceto the transcowl that biases the transcowl toward the deployed position,the force in the over-stow position greater than the force in the stowedposition.
 2. The system of claim 1, further comprising: a linkageassembly coupled to the door and to the transcowl, the linkage assemblyconfigured to cause the door to rotate between the first, second, andthird positions when the transcowl translates between the stowed,deployed position, and over-stow positions, respectively.
 3. The systemof claim 1, wherein: the lock includes a pin that translates between anextended position and a retracted position when the lock is in thelocked position and the unlocked position, respectively, the pin havinga groove formed in a portion thereof; and a portion of the transcowl isdisposed in the groove when the lock is in the locked position and thetranscowl is in the stowed position to thereby prevent the pin frommoving to the retracted position when the transcowl is in the stowedposition.
 4. The system of claim 1, wherein: the lock includes aplurality of lock segments that are each movable between an extendedposition and a retracted position when the lock is in the lockedposition and the unlocked position, respectively; and a portion of thetranscowl is engaged by each of the lock segments when the lock is inthe locked position and the transcowl is in the stowed position tothereby prevent the lock segments from moving to the retracted positionwhen the transcowl is in the stowed position.
 5. The system of claim 1,wherein: the lock includes a hook that is rotatable between a firstrotational position and a second rotational position when the lock is inthe locked position and the unlocked position, respectively; and aportion of the transcowl is engaged by the hook when the lock is in thelocked position and the transcowl is in the stowed position to therebyprevent the hook from moving to the second rotational position when thetranscowl is in the stowed position.
 6. A thrust reverser system for aturbine engine, comprising: a support structure configured to be mountedto the turbine engine; a transcowl mounted on the support structure andincluding an inner surface, the transcowl mounted on the supportstructure and axially translatable, relative to the support structure,between (i) a stowed position, in which the transcowl is displaced fromthe support structure by a first distance to form a stowed positionaperture, (ii) a deployed position, in which the transcowl is displacedfrom the support structure a second distance that is larger than thefirst distance, and (iii) an over-stow position, in which the transcowlis displaced from the support structure by a third distance that is lessthan the first distance, thereby decreasing the size of the stowedposition aperture; a plurality of doors pivotally coupled to the supportstructure, each door including an outer surface and spaced apart fromthe transcowl to define a gap between the inner surface of the transcowland the outer surface of the door, each door rotatable between at leasta first position, a second position, and a third position when thetranscowl translates between the stowed position, the deployed position,and the over-stow position, respectively, each door configured, when itis in the second position, to redirect engine airflow to therebygenerate reverse thrust; a plurality of actuators coupled to the supportstructure and the transcowl, each actuator configured to supply anactuation force to move the transcowl between the stowed position, thedeployed position, and the over-stow position; a lock coupled to thesupport structure and movable between a locked position, in whichtranscowl translation toward the deployed position is prevented, and anunlocked position, in which transcowl translation toward the deployedposition is allowed, the lock configured so that it is prevented frommoving from the locked position to the unlocked position when thetranscowl is in the stowed position and is only able to move to theunlocked position when the transcowl is in the over-stow position; and afirst elastic element disposed within the stowed position aperture andengaging both the support structure and the transcowl at least when thetranscowl is in and between the stowed and over-stow positions, thefirst elastic element configured, when engaging both the supportstructure and the transcowl, to supply a force to the transcowl thatbiases the transcowl toward the deployed position, the force in theover-stow position greater than the force in the stowed position.
 7. Thesystem of claim 6, further comprising: at least one linkage assemblycoupled to each door and to the transcowl and configured to cause thedoors to rotate between the first, second, and third positions when thetranscowl translates between the stowed, deployed position, andover-stow positions, respectively.
 8. The system of claim 6, wherein:the lock includes a pin that translates between an extended position anda retracted position when the lock is in the locked position and theunlocked position, respectively, the pin having a groove formed in aportion thereof; and a portion of the transcowl is disposed in thegroove when the lock is in the locked position and the transcowl is inthe stowed position to thereby prevent the pin from moving to theretracted position when the transcowl is in the stowed position.
 9. Thesystem of claim 6, wherein: the lock includes a plurality of locksegments that are each movable between an extended position and aretracted position when the lock is in the locked position and theunlocked position, respectively; and a portion of the transcowl isengaged by each of the lock segments when the lock is in the lockedposition and the transcowl is in the stowed position to thereby preventthe lock segments from moving to the retracted position when thetranscowl is in the stowed position.
 10. The system of claim 6, wherein:the lock includes a hook that is rotatable between a first rotationalposition and a second rotational position when the lock is in the lockedposition and the unlocked position, respectively; and a portion of thetranscowl is engaged by the hook when the lock is in the locked positionand the transcowl is in the stowed position to thereby prevent the hookfrom moving to the second rotational position when the transcowl is inthe stowed position.
 11. A turbofan or turbojet engine, comprising: agas turbine engine; and a nacelle coupled to and at least partiallysurrounding the gas turbine engine, the nacelle comprising a thrustreverser system that includes: a support structure configured to bemounted to the turbine engine; a transcowl mounted on the supportstructure and axially translatable, relative to the support structure,between (i) a stowed position, in which the transcowl is displaced fromthe support structure by a first distance to form a stowed positionaperture, (ii) a deployed position, in which the transcowl is displacedfrom the support structure a second distance that is larger than thefirst distance, and (iii) an over-stow position, in which the transcowlis displaced from the support structure by a third distance that is lessthan the first distance, thereby decreasing the size of the stowedposition aperture; a plurality of doors pivotally coupled to the supportstructure, each door rotatable between at least a first position, asecond position, and a third position when the transcowl translatesbetween the stowed position, the deployed position, and the over-stowposition, respectively, each door configured, when it is in the secondposition, to redirect engine airflow to thereby generate reverse thrust;a plurality of actuators coupled to the support structure and thetranscowl, each actuator configured to supply an actuation force to movethe transcowl between the stowed position, the deployed position, andthe over-stow position; a lock coupled to the support structure andmovable between a locked position, in which transcowl translation towardthe deployed position is prevented, and an unlocked position, in whichtranscowl translation toward the deployed position is allowed, the lockconfigured so that it is prevented from moving from the locked positionto the unlocked position when the transcowl is in the stowed positionand is only able to move to the unlocked position when the transcowl isin the over-stow position; and a first elastic element disposed withinthe stowed position aperture and engaging both the support structure andthe transcowl at least when the transcowl is in and between the stowedand over-stow positions, the first elastic element configured, whenengaging both the support structure and the transcowl, to supply a forceto the transcowl that biases the transcowl toward the deployed position,the force in the over-stow position greater than the force in the stowedposition.
 12. The turbofan or turbojet engine of claim 11, furthercomprising: at least one linkage assembly coupled to each door and tothe transcowl and configured to cause the doors to rotate between thefirst, second, and third positions when the transcowl translates betweenthe stowed, deployed position, and over-stow positions, respectively.